Physical Science 12.3

Multiple Choice

A stationary figure skater pushes off the boards around an ice skating rink and begins gliding backward, away from the boards. Which law explains why the figure skater moves backward?

• the law of conservation of energy

• the law of inertia

• Newton’s second law

• Newton’s third law

Multiple Choice

A red puck with Velcro on its side is sliding toward a stationary blue Velcro puck of the same mass. The pucks will stick together upon contact. After contact, how will the red puck’s velocity compare to its initial velocity? (In this collision the law of conservation of momentum is obeyed, and friction is ignored.)

• The red puck’s velocity is the same as before

• The red puck’s velocity is the same magnitude but in the opposite direction

• The red puck’s velocity is half its initial velocity and in the same direction

• The red puck’s velocity is double its initial velocity and in the opposite direction